Heat sealing means for packaging machines



g 1966 J. 5. BARTLO ETAL 3,254,799

HEAT SEALING MEANS FOR PACKAGING MACHINES 4 Sheets-Sheet l Filed Sept.

INVENTORS JOHN s. BAR'TLO VOLKER R-GRUNDMANN BY akwpw w a antenna-7S 4Sheets-Sheet 2 INVENTORS JOHN 5, BARTLO axiom-r13 6 VOLKEJE' '2.GRUNDMANN Aug. 9, 1966 J. 5. BARTLO ETAL HEAT SEALING MEANS FORPACKAGING MACHINES Filed Sept. 9, 1963 1966 J. 5. BARTLO ETAL 3,264,799

HEAT SEALING MEANS FOR PACKAGING MACHINES E 1 9L 7 INVENTORJ l-IOHN S.BARTLO VOLKER R.GRUNDMANN BY F Haul g- 9, 1966 J. 5. BARTLO ETAL3,264,799

HEAT SEALING MEANS FOR PACKAGING MACHINES Filed Sept.

4 Sheets-Sheet 4 INVENTOR-S JOHN S. BARTLO VOLKER R.GRUNDMANN UnitedStates Patent 3,264,799 HEAT SEALlNG MEANS FOR PACKAGING MACHINES .lohnS. Bartlo, Longmeadow, Mass, and Volker R.

Grundmann, Windsor, Conn., assignors to Package Machinery Company, EastLongmeadow, Mass, a corpoi-anon of Massachusetts Filed ept. 9, 1963,Ser. No. 307,586 Claims. (Cl. 53379) The present invention relates toimprovements in packaging m-achines and more particularly to improvedmeans for heat sealing folded lwrapper portions.

The object of the invention is to provide simple and inexpensive meansfor registering a heat seal pattern on the end faces or other faces ofarticles against which wrapper portions are folded and lapped so thatthe pattern is spaced from the corner edges of the article, and furtherto provide for such registration on a wide range of article sizes with aminimum of adjacent and a minimum need of change parts.

The present invention has general utility for all heat scalable wrappermaterials, but finds particular advantage in sealing orientedpolypropylene and similar materials wherein contact by the heat sealingwith the corner edges of the articles is particularly undesirable.

In accomplishing applicants stated objects, heat sealing mechanism isprovided at the discharge end of the folding channel of a wrappingmachine and articles having 'wrapper extensions folded against theopposed end faces of the articles are advanced therepast by conveyormeans which maintain the articles in spaced relation. The heat sealingmechanism comprises heat sealing rollers mounted on opposite sides ofthe path of advance of the articles. The rollers each have a Workingcylindrical surface of a height less than that of the end faces of thearticles, with the lower and upper edges of the working surface beingspaced respectively beneath and above the upper and lower corner edgesof the end facm of the articles. Means are provided for rotating therollers at a rate such that the peripheral rate of the cylindricalworking surfaces is substantially the same as the rate of advance of thearticles. Means are provided for moving the articles into engagementwith the end faces of each article in such timed relation that therollers contact the articles at a point adjacent to and spaced from theleading corner edges thereof and then move the rollers out of engagementwith the articles in such timed relation that the last point ofengagement with the end faces is adjacent to and spaced from thetrailing corner edges of the articles, thereby producing a heat sealedpattern on the end faces of the article which is registered in relationthereto and spaced inwardly from the four corner edges thereof.

Similarly, where wrapper extensions are folded against each other on thebottom or other face of an article, a single roll could similarly beemployed and the same means employed to so register a heat sealedpattern on such other face.

The above and other related objects and features of the invention willbe apparent from a reading of the following description of thedisclosure found in the accompanying drawings and the novelty thereofpointed out in the appended claims.

In the drawings:

FIG. 1 is a perspective view of a wrapped article ill-ustrating a heatseal as formed in accordance with the present invention;

FIG. 2 is a view in transverse section showing the discharge end of awrapping machine incorporating the heat sealing mechanism of the presentinvention;

FIG. 3 is a plan view, with portions broken away, of the heat sealingmechanism;

Patented August 9, 1966 ice FIG. 4 is a section taken on line IV-IV inFIG. 3;

FIG. 5 is a side elevation, partly in section, of the heat sealingmechanism;

FIG. 6 is a section taken on line VIVI in FIG. 3; and

FIG. 7 is a schematic diagram of electric air circuits employed herein.

Referring now to the drawings, articles a are discharged from thefolding channel of a wrapping machine by overhead conveyor flights 10(FIGS. 2 and 3). The flights 10 are driven by known means and advancethe articles a in spaced relation along a platform 12. The articles areguided by side rails 14 and are held down by top guides 15. Wrapperportions are folded against the end faces of each article a in a mannerillustrated in FIG. 1 by known means in the folding channel. It will beapparent to those skilled in the art that the folded wrapper portionscould have other configurations.

The present invention deals with the heat sealing of these foldedwrapper portions as .the articles are discharged from the wrappingmachine. Heat sealing rollers 16 mounted on opposite sides of the pathof advance of the articles a are employed for this purpose. The mounting of each roller 16 is substantially identical and counterparts of thedescribed right hand mounting are provided for the left hand mounting.

Each roller 16 comprises a heated cylinder 18 (FIG. 6), having aplurality of rings 20 telescoped thereover. The cylinder 18 is securedto a flange 24 formed at the upper end of a hollow spindle 26, by screws28. The lowermost ring 20 rests on the flange 24 and the stack of ringsplus spacers 30 (which are also telescoped over the cylinder 18) areheld in place by a retainer 32 which is secured to the upper end of thecylinder *18 by screws 34.

The spindle 26 is rotatably mounted by bearings 36 at the free end of anarm 38. A slip ring assembly 40 is secured to the lower end of thespindle 26 and provides for flow of electrical current to heatingelements (not shown) mounted within the cylinder 18. A junction box 42is secured to the arm 38 and an electrical cable 0 provides currentthrough brushes 44 (FIG. 2) engaging the slip ring assembly 40 toenergize the above-mentioned heating elements. If desired, connectionscan also be made in a known manner for the thermostatic control of theheating elements.

The arm 33 is pivotally mounted on a post 46 (FIG. 6) which projectsupwardly from a bracket 48. The bracket 48 (FIGS. 2, 3 and 5) isslidably mounted on a cross bar 5!) with gibs 52 secured thereto andembracing the cross bar. The bracket 48 is also supported by a rotatingshaft 54 (FIG. 3 in particular) which is journaled by bearings 55mounted in legs 57 of bracket 48 which straddle a spiral gear 56 mountedon the shaft 54. The gear 56 is keyed to a sleeve 58 which is slidableon the shaft 54 and held in fixed relation to the bearings 55 by snaprings -60. The gear is centered relative to the sleeve 58 by collars 62.A slide key 64 is received by slots in the sleeve $8 and shaft 54 totransmit rotation from the shaft 54 to the gear 56 and at the same timeto permit sliding movement of the bracket 48 relative to the shaft 54 tothereby enable adjustment of the sealing mechanism for different packagewidths.

The gear 56 meshes with a gear 66 which is secured to a vertical shaft68 that is journaled by bearings 70 on the bracket 48. A sprocket 72 issecured to the upper end of the shaft 68 and has a chain 74- trainedtherearound. The chain 74 is also trained around a sprocket 76 which isformed integrally with the spindle 26. An idler sprocket 78 is rotatablymounted on a slide 80 which is adjustable relative to the arm 38 toproperly tension the chain 74. Screw 82 is provided to tighten the slide80 r, O in an adjusted position for proper tension of the chain 74.

Shaft 54 is continuously rotated by the same power source as issued forthe wrapping machine. The relative rollers 16 are selected so that theperipheral rate of the rings 20 are substantialy the same as the rate atwhich the articles a are advanced by the conveyor flights at 10.

Oppositely threaded screws 102 are received by threaded members 104- oneach of the brackets 48. Means are provided for rotating the screws 102simultaneously to move the heat sealing elements inwardly or outwardly,as desired, to adjust for varying package widths.

Each roller 16 is moved into and out of operative engagement with theend faces of the articles by an air cylinder 84 (FIGS. 2, 3 and havingone end pivotally mounted on an extension 85 of the bracket 48 by ashoulder screw 86. The air cylinder 84 has a piston rod 88 projectingtherefrom which is pivotally connected at 90 to a bell crank 92. Thebell crank is pivotally mounted at 94 to a lug 96 projecting from thebracket 48. A pair of links 98 are connected at one end to the bellcrank 92 and at their opposite ends to a lug 100 projecting from the arm38. FIG. 3 illustrates the roller 16 in its operative positon with thepiston rod 88 fully projected. When the piston rod 88 is retracted, thearm 38, and with it the roller 16, is swung outwardly to a positionspaced from the path of advance from the article a.

A pair of detector switches 106, 108 are provided for actuating movementof the roller 16 into and out of engagement with the end faces of thearticles. These switches are respectively secured to plates 110, 112 byscrews 114. The plates 110, 112 are secured to a central mounting pad116 by a screw 118 passing through slots in the plates 110, 112 toprovide for longitudinal adjustment of the switches 106, 108. Themounting pad 116 is secured to a bracket 120 by screws 122. The bracket120 has a junction box 124 mounted thereon to provide for electricalconnections to the switches 106, 108. The bracket 120 is itself securedto the cross bar 50 by screws 126. The switches have actuator arms 128,130 respectively which project above the discharge platform 12 and aredepressed to actuate the switches 106, 108.

FIG. 7 in a highly diagrammatical form indicates the electricalconnections of the switches 106, 108. It will there be seen that theseswitches are connected in series with each other and in series with afourway solenoid valve S across a current source. The solenoid valvecontrols flow of compressed air to opposite ends of the air cylinder 84.When either of the switches 106 or 108 is open, the solenoid valve isdeenergized to maintain the heated rollers 16 in positions spaced fromthe path of advance of the articles. When both of the switches 106, 108are closed, the solenoid valve is energized and flow of air is reversedto project the piston rod 88 and thereby displace the rollers 16 intopositions engaging opposite end faces of the articles a.

In operation, as the leading edge of an article first depresses the arms128 and then 130, the solenoid valve S is energized, causing the rollers16 to swing into engagement with the opposed end faces of the article a.The timing is such that the rings which actually contact the article aengage the end faces thereof at a point adjacent to, but spaced inwardlyfrom, the leading corner edges of the article. Likewise, when thetrailing edge of the article passes over the switch arm 128, the switch106 is opened and the solenoid valve is deenergized, causing the pistonrod 88 to retract and thereby space the roller 16 from the path ofadvance of the articles. Here again the timing is such that the lastcontact of the rings 20 with the end faces of the article is at a pointadjacent to but spaced from the trailing corner edges of the articles.It will further be noted that the arrangement of the rings 20 in aheightwise sense is such that the highest and lowest points of contactthereof are at points respectively spaced from and adjacent the upperand lower corner edges of the article. In this fashion it is possible toregister a heat sealed pattern on the end faces of the article which isspaced from the four corner edges thereof.

This feature is of particular value in overcoming the tendency ofwrapper films tending to thin out or burn through at the corner edgeswhen heat sealing the folded wrapper ends. This is particularly truewith less rigid article where conventional sealing means engaging theentire face of the article tend to concentrate heat and pressure on thewrapper film at the corner edges as the central portions of the endfaces of the article are deflected.

The present invention finds even greater utility in sealing certainnewly available wrapper films such as oriented polypropylene, whereengagement of the heated element of the corner edge is particularlyundesirable since there would be a tendency to substantially weaken thewrapper even if no thinning occurred. In this latter connection, it willbe noted that the rings 20 have a finely divided knurled surface. Thissurface has been found particularly advantageous in overcoming thedifficulties of heat sealing oriented polypropylene. The use of knurledsurfaces as such is known in the art.

The present sealing mechanism further finds great utility in its abilityto handle a wide range of sizes with a minimum of changeover time fromone size to another. Thus, it has already been pointed out that thesealing mechanism is mounted for lateral movement to accommodatedifferent width of articles. As for article length, little or noadjustment of the longitudinal position of the switches 106, 108 isrequired. Further, to this, the rings 20 are adapted to facilitateaccurate registration of a heat sealed pattern for articles of differentheights. The sealing rings 20 are for this reason of different heightsand telescoped over the cylinder 18 simply by selecting the propercombination of rings 20 and placing the spacer 30 below the unneededrings, any height of article within a given size range can be readilyaccommodated.

It will further be pointed out that actuation of the' solenoid valvecontrolling flow of air to the cylinder 84 could also be provided for bythe use of cam means rotating in fixed relation to the advance of theconveyor flights 10. Different lengths of articles would be accommodatedby providing a variable cam construction known to those in the art whichwould give a variable energization time for the solenoid valve,dependent upon the length of article.

Again it will be pointed out that the same concepts could be employedwhere other configurations of wrapper folds are used, as for example,where the wrapper folds require the use of a single roll sealing againstthe bottom of the article.

Having thus described the invention, what is claimed as novel anddesired to be secured by Letters Patent of the United States is:

1. In combination with a packaging machine having a folding channel forfolding wrapper extensions in lapped relation against once face ofarticles advanced therethrough, means for advancing articles through thefolding channel, heat sealing mechanism comprising a cylindrical heatsealing roller mounted in opposed relation to said one face, means forrotating said roller about an axis parallel to said one face and normalto the path of advance of the articles at a peripheral rateapproximating the rate of advance of the articles, the axial length ofthe working cylindrical surface of the roller being less than that ofthe opposed one face of the articles and spaced inwardly from the endsthereof, and means for moving the roller into engagement with said oneface of each article in such timed relation that the roller contactssaid one face at a point adjacent to and spaced inwardly from theleading corner edge thereof and means for moving the roller out ofengagement with said articles in such timed relation that the last pointof engagement with said one face is adjacent to and spaced from thetrailing corner edge of the articles to thereby produce a heat sealedpattern on said one face of each article which is registered in relationthereto and spaced inwardly from the four corner edges thereof.

2. A combination as in claim 1 wherein the heat sealing roller comprisesa central cylinder, a plurality of rings of different axial lengthstelescoped thereover, and a spacer of lesser diameter than said ringstelescoped over said cylinder and adapted to separate one or more of therings having the specified axial length less than that of the one faceof the article from the remainder of the rings and means for replaceablyholding said rings and spacer in assembled relation on said cylinderwhereby the rings and spacer may be readily positioned on said cylinderto obtain the proper axial length of working surface for engaging a widerange of article dimensions.

3. In combination with a packaging machine having a folding channel forfolding wrapper extensions against the opposed end faces of articles,and means for advancing the articles from the folding channel in spacedrelation, heat sealing mechanism comprising heat sealing rollers mountedon opposite sides of the path of advance of articles from the foldingchannel, said rollers each having a working cylindrical surface of aheight less than that of the end faces of the articles and with thelower and upper edges spaced respectively beneath and above the upperand lower corner edges of the end faces of the articles, means forrotating the'rollers at a rate such that the peripheral rate of saidcylindrical surfaces is substantially the same as the rate of advance ofthe articles, and means for moving the rollers into engagement with theend faces of each article in such timed relation that the rollerscontact the articles at a point adjacent to and spaced inwardly from theleading corner edges thereof, and means for moving the rollers out ofengagement with the articles in such timed relation that the last pointof engagement with said end faces is adjacent to and spaced from thetrailing corner edges of the articles to thereby produce a heat sealedpattern on the end faces of each article which is registered in relationthereto and spaced inwardly from the four corner edges thereof.

4. A combination as in claim 3 wherein each roller comprises a centralcylinder, a plurality of rings of different heights telescoped thereoverand a spacer of lesser diameter than said rings also telescoped oversaid cylinder and adapted to separate one or more of the lower ringshaving the specified height less than that of the article end faces fromthe remainder of the rings and means for releasably holding said ringsand separator in assembled relation on said cylinder whereby the ringsand separator may be readily positioned on said cylinder to obtain theproper height of surface for engaging a wide range of article heights.

5. The combination as in claim 3 wherein the rollers are each mounted onan arm and each arm is pivotally mounted to move the rollers into andout of engagement with the end faces of the articles in the specifiedtimed relationships.

6. A combination as in claim 5 wherein an air motor is provided forpivoting said arms to so move the rollers and switch means are providedfor actuating operation of said motors dependent on the points ofadvance of the leading and trailing edges of the articles.

7. A combination as in claim 3 wherein each roller is mounted on ahollow spindle journaled on an arm, a slip ring assembly is secured tothe lower end of each spindle and connections are provided for supplyingcurrent to energize heating elements for said rollers, and furtherwherein a bracket is provided for each arm, each bracket having a postfor the pivotal mounting of the arm associated therewith.

8. A combination as in claim 7 wherein each of said posts is hollow anda shaft extends therethrough with a sprocket at its other end, eachhollow spindle has a sprocket thereon, chains connect the shaftsprockets and spindle sprockets respectively, and means are provided forrotating said shafts to thereby provide the means for rotating saidrollers.

9. A combination as in claim 8 wherein said brackets are slidablymounted on a fixed member disposed transverse to the path of advance ofsaid articles and the means for rotating said shafts comprises a gearsecured to the lower end of each shaft, a transverse rotating shaft,gears slidably mounted on said shaft and meshing respectively with theaforesaid gears, said brackets having portions positioning said slidablegears in meshing relation with the first mentioned gears whereby theheat sealing rollers may be adjusted for different widths of articles.

10. A combination as in claim 9 wherein each roller comprises a centralcylinder, a plurality of rings of different heights telescoped thereoverand a separator of lesser diameter than said rings also telescoped oversaid cylinder and adapted to separate one or more of the lower ringshaving the specified height less than that of the article end faces fromthe remainder of the rings and means for releasably holding said ringsand separator in assembled relation on said cylinder whereby the ringsand separator may be readily positioned on said cylinder to obtain theproper height of surface for engaging a wide range of article heights.

No references cited.

FRANK E. BAILEY, Primary Examiner. P. POHL, Assistant Examiner.

1. IN COMBINATION WITH A PACKAGING MACHINE HAVING A FOLDING CHANNEL FORFOLDING WRAPPER EXTENSIONS IN LAPPED RELATION AGAINST ONCE FACE OFARTICLES ADVANCED THERETHROUGH, MEANS FOR ADVANCING ARTICLES THROUGH THEFOLDING CHANNEL, HEAT SEALING MECHANISM COMPRISING A CYLINDRICAL HEATSEALING ROLLER MOUNTED IN OPPOSED RELATION TO SAID ONE FACE, MEANS FORROTATING SAID ROLLER ABOUT AN AXIS PARALLEL TO SAID ONE FACE AND NORMALTO THE PATH OF ADVANCE OF THE ARTICLES AT A PERIPHERAL RATEAPPROXIMATING THE RATE OF ADVANCE OF THE ARTICLES, THE AXIAL LENGTH OFTHE WORKING CYLINDRICAL SURFACE OF THE ROLLER BEING LESS THAN THAT OFTHE OPPOSED ONE FACE OF THE ARTICLES AND SPACED INWARDLY FROM THE ENDSTHEREOF, AND MEANS FOR MOVING THE ROLLER INTO ENGAGEMENT WITH SAID ONEFACE OF EACH ARTICLE IN SUCH TIMED RELATION THAT THE ROLLER CONTACTSSAID ONE FACE AT A POINT ADJACENT TO AND SPACED INWARDLY FROM THELEADING CORNER EDGE THEREOF AND MEANS FOR MOVING THE ROLLER OUT OFENGAGEMENT WITH SAID ARTICLES IN SUCH TIMED RELATION THAT THE LAST POINTOF ENGAGEMENT WITH SAID ONE FACE IS ADJACENT TO AND SPACED FROM THETRAILING CORNER EDGE OF THE ARTICLES TO THEREBY PRODUCED A HEAT SEALEDPATTERN ON SAID ONE FACE OF EACH ARTICLE WHICH IS REGISTERED IN RELATIONTHERETO AND SPACED INWARDLY FROM THE FOUR CORNER EDGES THEREOF.